Injection apparatus for injecting an activated fluid into a well-bore and related injection method

ABSTRACT

An injection apparatus for injecting an activated fluid and an activated chemical fluid mixture into a well-bore is disclosed. Then, an injection method for injecting an activated fluid into a well-bore is also disclosed. A particular application to the oilfield industry, for example in cementing operation is encompassed. The apparatus and the method of use is fully automatic.

FIELD OF THE INVENTION

The invention relates to an injection apparatus for injecting anactivated fluid (e.g. an activated chemical fluid mixture) into awell-bore. The invention also relates to an injection method forinjecting an activated fluid into a well-bore.

A particular application of the invention relates to the oilfieldindustry, for example in cementing operation.

BACKGROUND OF THE INVENTION

During a hydrocarbon well drilling operation and after a hydrocarbonwell has been drilled, various fluid injecting operations are generallycarried out. The fluid injecting operations serves various purposes, forexample delivering a chemical mixture into a fluid present in theborehole for consolidation purpose or fracturing purpose, or deliveringa chemical mixture into a cement slurry for borehole cementingoperation. These operations are well known in the oilfield industry andare described for example in U.S. Pat. No. 3,273,647, U.S. Pat. No.4,415,269 and patent application EP 1223303. FIG. 1 schematically showsa typical onshore hydrocarbon well location and equipments WE above ahydrocarbon geological formation GF after drilling operation has beencarried out and after a casing string CS has been run. At this stage,the well-bore WB is a bore-hole generally filled with various fluidmixtures (e.g. the drilling mud or the like). The equipment WE comprisesa drilling rig DR for running the casing string CS in the bore-hole,cementing equipment comprising cement silo CR and pumping arrangementCP, and a well head and stuffing box arrangement WH providing a sealingfor deploying the casing string CS or pumping down the cement into thegenerally pressurized well-bore WB.

Subsequently, cementing operations are generally undertaken to seal theannulus AN (i.e. the space between the well-bore WB and the casing CSwhere fluid can flow). A first application is primary cementing whichpurpose is to achieve hydraulic isolation around the casing. Otherapplications are remedial cementing which purposes are to stabilize thewell-bore, to seal a lost circulation zone, to set a plug in an existingwell or to plug a well so that it may be abandoned. The cement may bepumped into the well casing through a casing shoe CI near the bottom ofthe bore-hole or a cementing valve installed in the casing so that thecement is positioned in the desired zone.

Cementing engineers prepare the cementing operations by determining thevolume and physical properties of cement slurry and other fluids pumpedbefore and after the cement slurry. In many situations, chemicaladditives are mixed with the cement slurry in order to modify thecharacteristics of the slurry or set cement. Cement additives may bebroadly categorized as accelerators (i.e. for reducing the time requiredfor the set cement to develop sufficient compressive strength to enablefurther operations to be carried out), retarders (i.e. for increasingthe thickening time of cement slurries to enable proper placement),dispersants (i.e. for reducing the cement slurry viscosity to improvefluid-flow characteristics), extenders (i.e. for decreasing the densityor increasing the yield of a cement slurry), weighting agents (i.e. forincreasing or lightening the slurry weight), fluid-loss orlost-circulation additives (i.e. for controlling the loss of fluid tothe formation through filtration) and special additives designed forspecific operating conditions.

Because cement additives have an effect as soon as they are mixed withthe cement slurry, it is important that cement additives are injected inthe cement slurry at the proper time and at the desired location in thewell-bore.

Apparatus for injecting cement additives are known. For example, U.S.Pat. No. 5,533,570 discloses an apparatus for injecting a fluid into awell-bore. This apparatus comprises a fluid holding chamber that ispumped down the well-bore, and a valve means for opening a port of thechamber and delivering the fluid at a desired time and location (forexample through an opening of the casing shoe). However, this apparatusdoes not include an efficient additive dosing system. Further, theapparatus is non-retrievable.

SUMMARY OF THE INVENTION

One goal of the invention is to propose an apparatus for injecting anactivated chemical fluid mixture into a well-bore that overcome at leastone of the shortcomings of prior art apparatus.

According to the invention, the apparatus for injecting an activatedchemical fluid mixture into a well-bore comprises a valve arrangement,an activation fluid reservoir and a dosing and mixing arrangementcoupled to each other. The valve arrangement can be remotely activatedfrom the surface. The apparatus is coupled to a standard drill-pipestring or a casing string in order to receive a flow of a first fluidand activation commands for the valve arrangement. The valve arrangementactivates and controls the dosing and mixing arrangement so as to injecta determined quantity of activation fluid into the first fluid. Theapparatus can be coupled to any casing, cementing or drillingequipments, and provides to these equipments a flow of a second fluidthat may be constituted of an activated chemical fluid mixture.

More precisely, the present invention relates to an injection apparatusfor injecting an activated fluid into a well-bore comprising a reservoircontaining an activation fluid AF. The injection apparatus furthercomprises:

-   -   a valve arrangement adapted to be coupled to a pipe (drill-stem        or casing string) for receiving a first fluid flow,    -   a dosing and mixing arrangement coupled to the reservoir and to        the valve arrangement.

The valve arrangement has a rest configuration in which the injectionapparatus provides a non-activated fluid mixture and an activatedconfiguration in which the injection apparatus provides an activatedfluid mixture.

The dosing and mixing arrangement comprises an engine part mechanicallycoupled to a pumping part. The engine part runs the pumping part and thepumping part sucks the activation fluid of the reservoir when the valvearrangement is in the activated configuration. The dosing and mixingarrangement mixes the activation fluid with the first fluid and providesan activated fluid mixture flow at an outlet.

Advantageously, the injection apparatus further comprises a pressureadjusting arrangement for adjusting the pressure inside the reservoir tothe pressure inside the pipe (a reservoir comprising a piston or areservoir comprising an equalization port).

Advantageously, the valve arrangement comprises a sliding sleeve havinga first dart catcher for remotely activating the valve arrangement fromthe rest configuration to the activated configuration.

Other characteristics of the injection apparatus will be furtherdescribed in the detailed description herein below.

The apparatus for injecting an activated chemical fluid mixture into awell-bore of the invention is adapted to be connected to a drill-stringor a casing string. The apparatus is fully retrievable: it can beremoved from the well-bore when operations are completed and re-used forsubsequent operations. Alternatively, it can be drilled if rig-timeneeds to be saved. It enables a truly proportional dosing of anactivation fluid into a fluid to be activated. Finally, it can beremotely controlled.

Consequently, the apparatus of the invention is flexible, cheap andefficient to use in various oilfield industry oriented applications.

In particular, the apparatus can be used in casing stab-in situation(i.e. injecting a chemical activator into a cement slurry directly atthe casing shoe), in drilling situation (i.e. injecting a chemicalactivator into a reactive fluid pumped through the drill-string) forwell-bore walls or plugs voids consolidation, in cement plug situation(i.e. injecting a chemical activator into a fluid for temporary ofpermanent sealing inside the well-bore), in casing-drilling situation,or in coiled-tubing operation (i.e. injecting a chemical activator intothe main fluid for coiled tubing fracturing or remedial cementing).

The invention also relates to an injection method for injecting anactivated fluid into a well-bore. The method comprises the steps of:

-   -   running the injection apparatus of the invention at a proper        location in the well-bore, the valve arrangement being in a rest        configuration,    -   letting flow a first fluid through the apparatus into the        well-bore,    -   activating the valve arrangement of the injection apparatus in        an activated configuration in which a first portion of the first        fluid activates a pumping part sucking the activation fluid of        the reservoir,    -   mixing the sucked activation fluid with the first portion of the        first fluid, and    -   injecting an activated fluid mixture flow at an outlet.

Optionally, the method further comprises the steps of activating thevalve arrangement of the injection apparatus in a by-pass position inwhich a second portion of the first fluid flows directly to the outlet(non activated fluid flow).

Advantageously, the activating steps are remotely controlled from asurface equipment.

Thus, the invention provides an efficient apparatus and method which canbe run at a desired location in a well-bore and remotely activated at aparticular moment for injecting an additive contained in a reservoirinto the well-bore.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and not limitedto the accompanying figures, in which like references indicate similarelements:

FIG. 1 schematically shows a typical onshore hydrocarbon well locationand equipments;

FIG. 2 schematically illustrates an apparatus for injecting a chemicalfluid mixture into a well-bore according to the invention;

FIGS. 3.A, 3.B and 3.C schematically illustrate the valve arrangement ofthe apparatus of FIG. 2 and its various positions during operation;

FIG. 4.A schematically illustrates a first embodiment of the dosing andmixing arrangement of the apparatus of FIG. 2;

FIG. 4.B schematically illustrates a second embodiment of the dosing andmixing arrangement of the apparatus of FIG. 2;

FIG. 5.A schematically illustrates a first application of the invention;

FIGS. 5.B and 5.C are detailed cross-section views of the firstapplication of FIG. 5.A;

FIG. 6.A schematically illustrates a second application of theinvention;

FIGS. 6.B and 6.C are detailed cross-section views of the secondapplication of FIG. 6.A;

FIG. 7.A schematically illustrates a third application of the invention;and

FIGS. 7.B and 7.C are detailed cross-section views of the thirdapplication of FIG. 7.A.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 was already described in relation with the background of theinvention.

FIG. 2 schematically illustrates an apparatus 1 for injecting anactivated chemical fluid mixture into a well-bore.

The apparatus 1 for injecting a chemical fluid mixture is fitted intothe casing CS. The apparatus is coupled by its upper part to a standarddrill-pipe string 6. The apparatus is coupled by its lower part to anyequipment such as a standard float equipment of a stab-in casing, acasing drilling or casing shoe, or left as such for other drilling orcementing applications. The apparatus receives through an inlet 7 a flowof a first fluid F1 from the drill-pipe string 6 and provides through anoutlet 8 a flow of a second fluid F2.

The apparatus 1 for injecting a chemical fluid mixture comprises a valvearrangement 2, a reservoir 3, a dosing and mixing arrangement 4 andshunt tubes 9, 10.

The valve arrangement 2 is coupled to the drill-pipe string 6 ordirectly to a casing element of the casing string and receives the flowof the first fluid F1. The valve arrangement is also coupled to thereservoir 3 through a first reservoir conduit 3D and to the dosing andmixing arrangement 4 through a first shunt tube 9. The valve arrangementmay also be coupled directly after the mixing arrangement 5 through asecond shunt tube 10. The valve arrangement can be remotely activated(i.e. opening or closing of valves and ports) from the surface.Depending on the configuration of the valve arrangement 2, the fluid F1may be divided into a first portion F1′ flowing through the shunt tube9, or a second portion F1″ flowing through the second shunt tube 10 anda third portion F1′″ flowing though the reservoir conduit 3D.

The reservoir 3 contains an activation fluid AF. The activation fluidmay be pressurized by means of a piston 3B when submitted to thepressure of the third flow portion F1′″ flowing through the conduit 3Dto an upper port 3A into an upper part of the reservoir. The activationfluid AF may flow through a lower port 3C and a second reservoir conduit3E into the dosing and mixing arrangement 4. The piston 3B also acts asa mechanical plug separating the activation fluid AF from the thirdfluid portion F1′″. The reservoir has for example a cylindrical shapeand the piston is a plug similar to the standard plugs used in primarycementing. The reservoir volume (diameter, length) can be very easilyadapted to each situation of use of the apparatus, namely quantity ofactivation fluid to be injected or available place within the casingstring, etc. . . .

Alternatively, the conduit 3D, the upper port 3A and the piston 3B maybe replaced by an equalization port for automatically adjusting thepressure inside the reservoir 3 to the pressure inside the drill-pipe orthe casing string. In this case, the reservoir may be a rubber bladder.The bladder membrane submitted to the tubing pressure through theequalization port plays the role of the piston relatively to theactivation fluid.

The dosing and mixing arrangement 4 is coupled to the first shunt tube9. It is also coupled to the lower port 3C of the reservoir by theconduit 3E and may receive a portion of the activation fluid AFcontained in the reservoir. The dosing and mixing arrangement determinesthe ratio of activation fluid AF injected into the first fluid flow F1(in fact into the first portion F1′ of the first fluid flow).

The dosing and mixing arrangement 4 provides the second fluid flow F2 tothe outlet 8. It insures a proper mixing of the injected activationfluid AF with the first portion F1′ of the first fluid flow.

Alternatively, a complementary mixing arrangement may be coupleddownstream to the dosing and mixing arrangement.

The second shunt tube 10 couples the valve arrangement directly to theoutlet 8. It acts as a side conduit for providing, at the outlet 8, asecond portion F1″ of the first fluid flow that does not need to beactivated by the activation fluid. In this case, the second fluid F2flowing through the outlet 8 is chemically identical to the first fluidF1 flowing through the inlet 7.

The first and second shunt tubes 9, 10 are conduits by-passing thereservoir 3 and attached to its periphery. The shunt tubes can bedesigned with various diameters and lengths adapted to the variousspecific use of the apparatus.

The operation principle of the apparatus 1 for injecting an activatedfluid mixture into a well-bore will be explained herein below inrelation with FIGS. 3 and 4.

FIGS. 3.A, 3.B and 3.C schematically illustrate the valve arrangement 2and its various positions during operation.

The valve arrangement 2 comprises a sliding sleeve 21. The slidingsleeve 21 is hollow so as to let flow the first fluid F1. It alsocomprises a side opening 24 for letting flow a portion of the firstfluid F1. The sliding sleeve comprises a first dart catcher 22 andoptionally a second dart catcher 23. The dart catcher can be remotelyactivated by a dart sent from the surface in the first fluid F1 throughthe drill-pipe string 6 or the casing string CS. This activation of thedart catcher determines different operating configuration or position ofthe valve arrangement.

The valve arrangement 2 comprises a first side conduit 25 connected tothe first reservoir conduit 3D and the first shunt tube 9, andoptionally a second side conduit 26.

According to another embodiment, the second shunt tube is omitted. Thisembodiment is advantageous when the apparatus does not need to befastened to a casing shoe.

FIG. 3.A shows the valve arrangement 2 in a first configuration (restconfiguration) before activation of the first dart catcher 22 by a firstdart. In this configuration, the sliding sleeve closes the first 25 andsecond 26 side conduits, and the first fluid flows though the hollowsliding sleeve directly into the second shunt tube 10 as fluid flow F1″.

FIG. 3.B shows the valve arrangement 2 in a second configuration(activated configuration) after activation of the first dart catcher 22by a first dart 27. In this configuration, the sliding sleeve 21 opensthe side opening 24 and the dart closes one end of the sliding sleeve sothat the flow of the first fluid F1 is mainly diverted through the sideopening 24 into the first side conduit 25. Subsequently, the first fluidflow F1 splits as a third portion F1′″ flowing into the reservoirconduit 3D and a first portion F1′ flowing into the first shunt tube 9.The third portion F1′″ flowing into the reservoir conduit 3D pressurizesthe reservoir 3 by acting on the piston 3B (see FIG. 2).

The first portion F1′ flowing into the first shunt tube 9 activates thedosing and mixing arrangement 4 as it will be further described hereinbelow.

FIG. 3.C shows the valve arrangement 2 in an optional thirdconfiguration (by-pass configuration) after activation of the seconddart catcher 23 by a second dart 28. In this configuration, the slidingsleeve 21 opens the second side conduit 26 and closes the side opening24 so that the first fluid F1 is mainly diverted through the second sideconduit 26. The first fluid flows directly into the second shunt tube 10as fluid flow F1″ which corresponds to a non-activated fluid chemicallyidentical to the first fluid F1.

The first and second darts and the corresponding dart catchers are sizedso that the first dart activates the first dart catcher and cannotactivate the second dart catcher. The first and second darts of theabove described embodiment are of spherical shape. However, it willappear obvious for a man skilled in the art that others kinds of shapeare possible, and that others kinds of catcher (e.g. plug catcher) canalso achieve the same remote activation function (e.g. see theapplication examples hereinafter).

FIGS. 4.A and 4.B schematically show the dosing and mixing arrangement 4according to a first and a second embodiment respectively.

The dosing and mixing arrangement 4 comprises an engine part 31, apumping part 32 and a gearing part 33.

The engine part 31 is coupled to the valve arrangement by the firstshunt tube 9. The pumping part 32 is coupled to the reservoir by thesecond reservoir conduit 3E. When the valve arrangement is in theactivated configuration, the flow of the first portion F1′ of the firstfluid activates the engine part 31. The engine part 31 produces amechanical movement that activates the pumping part 32 through thegearing part 33 (schematically illustrated by the dotted lines). Whenactivated, the pumping part 32 sucks the activation fluid FA from thereservoir (that may be pressurized by the third portion F1′″ of thefirst fluid flow). The gearing part 33 allows selecting the volume ratioof the two flows, namely the activation fluid FA and the first portionF1′ of the first fluid.

Advantageously, the engine part and the pumping part are progressivecavity or helical rotor type pumps. These types of pump are also knownas Moineau pump and consists of a helical rotor which rotates inside ahelical stator. The geometry and dimensions of the rotor and stator aredesigned so that a double string of sealed cavities are formed when therotor turns into the stator. The cavities progress axially from thesuction to the discharge port of the pump, thus carrying the fluid. Therotation rate of the rotor is proportional to the fluid flow rate.

Alternatively, the pumping part may also form a peristaltic pump, thepumping part being coupled to a simple flexible tube compressed andreleased by the movement of the pumping part run by the engine part.

According to the first embodiment shown in FIG. 4.A, the dosing andmixing arrangement 4 further comprises a complementary mixingarrangement 5.

The first portion F1′ of the first fluid flows out of the engine part31, while the activation fluid FA flows out of the pumping part 32.

The complementary mixing arrangement 5 comprises a flow splitter 34, apre-mixing chamber 35 and a final-mixing chamber 36. The mixingarrangement insures a proper mixing of the first fluid flowing out ofthe engine part with the activation fluid FA flowing out of the pumpingpart.

The first portion F1′ flows through the flow splitter 34. The flowsplitter 34 is coupled to an inlet of the pre-mixing chamber 35 and toan inlet of the final-mixing chamber 36.

The pre-mixing chamber 35 is also coupled to the pumping part through aninjecting conduit 37. It insures a first mixing of the split portion F1′of the first fluid with the activation fluid FA. For improving themixing process, the injecting conduit may be a Venturi tube producing ajet of activation fluid in the pre-mixing chamber.

The final mixing chamber 36 is also coupled to outlet of the pre-mixingchamber. It insures a second mixing of the other split portion F1′ ofthe first fluid with the pre-mixed fluid mixture. The outlet of thefinal mixing chamber delivers a second fluid flow F2, namely anactivated fluid mixture.

The final mixing chamber outlet may include a float valve, preventingany back flow from the well-bore.

According to the second embodiment shown in FIG. 4.B, the engine part 31is positioned downstream of the pumping part 32. The activation fluidflows FA into the engine part 31 by its superior part. Thus, themovement of the engine part insures a proper mixing of the fluid to beactivated F1′ with the activation fluid flow FA. In this embodiment, thecomplementary mixing arrangement is not necessary as mixing alreadyoccurred properly in the dosing and mixing arrangement 4.

Three different applications will be described hereinafter in relationwith FIGS. 5, 6 and 7.

FIGS. 5.A, 5.B and 5.C relate to a first application of the inventioncorresponding to a cement plug located in a lost circulation zone (i.e.the activation fluid is used so that the fluid injected into the annuluscan become thick enough, or the cement setting time can be shortened tolimit losses). The injecting apparatus 101 is run at the bottom of thedrill stem 106. It is activated by a dart 127 sent from the surface intothe drill stem. The injecting apparatus 101 can be retrieved at the endof the injection operation.

FIGS. 5.B and 5.C shows a detailed cross-section view of the injectingapparatus 101 in a rest configuration and in an activated configurationrespectively.

The injecting apparatus 101 comprises a valve arrangement 102, areservoir 103 and a dosing and mixing arrangement 104. The injectingapparatus 101 is installed inside a standard casing or a specialhousing. The length of the injecting apparatus should be almost the sameas a casing length.

The valve arrangement 102 comprises a mandrel 109 and a sliding sleeve121.

The mandrel 109 is a tube having substantially the same diameter or lessthan the drill stem 106. It is coupled by a top part to the drill stemand receives through the inlet 107 the fluid flowing through the drillstem. It is coupled by a bottom part to at least one shunt tube 110. Thebottom part also comprises an abutment 109A. The sliding sleeve 121 isguided within the mandrel.

The sliding sleeve 121 comprises a dart catcher 122, first 124 andsecond 124′ openings and a top part 121A.

The valve arrangement can be in a rest configuration (FIG. 5.B) or in anactivated configuration (FIG. 5.C).

In the rest configuration, the first openings 124 enable the fluidflowing into the mandrel to be diverted into the shunt tube 110. Thesliding sleeve 121 can be maintained in the rest position by, forexample, a pin mechanism 121B.

In the activated configuration, the second openings 124′ enable thefluid flowing into the mandrel to be diverted into the dosing and mixingarrangement 104. The sliding sleeve 121 can be maintained in theactivated configuration when, for example, the top part 121A is incontact with the abutment 109A.

The dart catcher 122 enables to activate the valve arrangement from therest configuration to the activated configuration.

The reservoir 103 is an annular bladder. The annular bladder isinstalled around the mandrel 109.

The top extremity of the bladder comprises a filling hose 103B closed bya top plug 103A. The bottom extremity of the bladder comprises anevacuation hose closed by a bottom plug 103D. The extremities of thesehoses are secured in the injecting apparatus near both extremities ofthe mandrel. The plugs can be removed to fill or flush the reservoir.The top plug 103A or the bottom plug 103D may be equipped with a reliefvalve for automatically venting the air trapped in the bladder.

The reservoir 103 is connected to the dosing and mixing arrangement 104by a reservoir conduit 103E.

The pressure of the reservoir 103 is automatically adjusted to thepressure inside the drilling stem (hydrostatic pressure plus surfacepressure) and/or in the mandrel by means of at least one equalizationport 103C drilled in the mandrel 109. The equalization port 103Coperates as follows: the fluid in the mandrel penetrates in theequalization port and exerts its pressure onto the reservoir, thuspressurizing the reservoir. When the reservoir is an annular bladder, itis deformed until the pressures outside and inside the reservoir areequilibrated.

The dosing and mixing arrangement 104 comprises an engine part 131mechanically coupled to a pumping part 132. Advantageously, the enginepart 131 is a progressive cavity or helical rotor type pump and thepumping part 132 is a peristaltic pump. The progressive cavity pump iscoupled to the peristaltic pump by a driving shaft 133. The end of thereservoir conduit 103E is a flexible tube coupled to the peristalticpump.

The engine part 131 namely the progressive cavity pump is driven by anyfluid flowing through it. When a fluid flows through the engine part131, it makes the pumping part 132 namely the peristaltic pump torotate. The rotation of the peristaltic pump alternatively compressesand releases the flexible tube of the reservoir conduit 103E, thussucking the activation fluid AF out of the reservoir.

The engine part 131 is positioned downstream of the pumping part 132 inorder to ensure a better mixing of the fluid to be activated and theactivation fluid.

The peristaltic pump is well adapted as long as the required activationfluid injection rate is a few percents of the main flow rate.

The activated fluid is injected into the well-bore through the outlet108″ downstream of the engine part 131.

The injecting apparatus 101 for the first application operates asfollows.

In the rest configuration shown in FIG. 5.B, the injecting apparatus 101can be used to deliver a non activated fluid F1″ into the well-bore. Thesliding sleeve 121 of the valve arrangement 102 is positioned into themandrel 109 so that the fluid flowing into the mandrel is divertedthrough the first openings 124 into the shunt tube 110 towards the shunttube outlet 108′.

In order to activate the valve arrangement, a dart 127 is launched fromthe surface and transported by the fluid that is to be activated.

In the activated configuration shown in FIG. 5.C, the injectingapparatus 101 is used to deliver an activated fluid F2 into thewell-bore.

The dart catcher 122 of the sliding sleeve receives the dart transportedby the fluid. The dart catcher 122 is for example a particular profileof the sliding sleeve (narrow area) for stopping and sealing the dart127. When the dart lands in the dart catcher, the sliding sleeve acts asa plug and blocks the fluid flow. Consequently, the upstream pressurerises, thus creating a downward load that moves the sleeve in theactivated configuration. When the sliding sleeve is maintained in therest configuration by a pin mechanism, the downward load shears the pins121B and releases the sliding sleeve. The sliding sleeve 121 slidesdownward in the mandrel and the top part 121 A of the sliding sleevebumps into the abutment 109A of the mandrel.

In this configuration, the sliding sleeve 121 simultaneously closes theshunt tube 110 and diverts the flow through the second opening 124′towards the engine part 131. The engine part 131 begins to rotate andmakes the pumping part 132 to rotate, thus sucking the activation fluidAF out of the reservoir 103.

The activation fluid flow FA and the fluid flow F1′ to be activatedmixes together downstream of the pumping part 132 (i.e. in the enginepart 132). An activated fluid flow F2 is delivered in the annulus AN ofthe well-bore WB.

FIGS. 6.A, 6.B, 6.C relate to a second application corresponding to acasing cementation (i.e. the activation fluid is used so that the cementsetting time can be shortened to save rig time). The injecting apparatus201 is incorporated between the two casing elements CS1, CS2. It isactivated by a dart 227 sent from the surface through the casing. Theinjecting apparatus 201 may be drilled out at the end of the cementingoperation.

FIGS. 6.B and 6.C shows a detailed cross-section view of the injectingapparatus 201 in a rest configuration and in an activated configurationrespectively.

The injecting apparatus 201 comprises a valve arrangement 202, areservoir 203 and a dosing and mixing arrangement 204. The injectingapparatus 201 is installed inside two standard casings between casingelement CS1 and CS2 by means of a nipple CSN. The casing element CS2 maybe a casing shoe.

The valve arrangement 202 comprises a mandrel 209 and a sliding sleeve221.

The mandrel 209 is a tube having an inferior diameter than the casingCS1, CS2 diameter. It receives the fluid flowing through the casing.Because of the significant difference between the casing internaldiameter and the mandrel inside diameter, a double dart assembly DD isused for the activation operation. The mandrel 209 is coupled by a toppart to a superior dart catcher 222C having a size substantiallycorresponding to the internal size of the casing. The superior dartcatcher 222C is adapted to receive the double dart assembly DDtransported by the fluid. The mandrel 209 is coupled by a bottom part toat least one shunt tube 210. The bottom part also comprises an abutment209A. The sliding sleeve 221 is guided within the mandrel.

The sliding sleeve 221 comprises a inferior dart catcher 222A, first 224and second 224′ openings and a top part 221A.

The valve arrangement can be in a rest configuration (FIG. 6.B) or in anactivated configuration (FIG. 6.C).

In the rest configuration, the first openings 224 enable the fluidflowing into the mandrel to be diverted into the shunt tube 210. Thesliding sleeve 221 can be maintained in the rest configuration by, forexample, a pin mechanism 221B.

In the activated configuration, the second openings 224′ enable thefluid flowing into the mandrel to be diverted into the dosing and mixingarrangement 204. The sliding sleeve 221 can be maintained in theactivated configuration when, for example, the top part 221A is incontact with the abutment 209A.

The inferior dart catcher 222A enables to activate the valve arrangementfrom the rest configuration to the activated configuration.

The reservoir 203 is an annular bladder 203. The annular bladder isinstalled around the mandrel 209.

The top extremity of the bladder comprises a filling hose 203B closed bya top plug 203A. The bottom extremity of the bladder comprises anevacuation hose closed by a bottom plug 203D. The extremities of thesehoses are secured in the injecting apparatus near both extremities ofthe mandrel. The plugs can be removed to fill or flush the reservoir.The top plug 203A or the bottom plug 203D may be equipped with a reliefvalve for automatically venting the air trapped in the bladder.

The reservoir is connected to the dosing and mixing arrangement 204 by areservoir conduit 203E.

The pressure of the reservoir 203 is automatically adjusted to thepressure inside the casing and/or in the mandrel by means of at leastone equalization port 203C drilled in the mandrel 209. The equalizationport 203C operates as follows: the fluid in the mandrel penetrates inthe equalization port and exerts its pressure onto the reservoir, thuspressurizing the reservoir. When the reservoir is an annular bladder, itis deformed until the pressures outside and inside the reservoir areequilibrated.

The dosing and mixing arrangement 204 comprises an engine part 231mechanically coupled to a pumping part 232. Advantageously, the enginepart 231 is a progressive cavity or helical rotor type pump and thepumping part 232 is a peristaltic pump. The progressive cavity pump iscoupled to the peristaltic pump by a driving shaft 233. The end of thereservoir conduit 203E is a flexible tube coupled to the peristalticpump. The engine part 231 is driven by any fluid flowing through it.When a fluid flows through the engine part 231, it makes the pumpingpart 232 to rotate. The rotation of the peristaltic pump alternativelycompresses and releases the flexible tube of the reservoir conduit 203E,thus sucking the activation fluid AF out of the reservoir 203. Theengine part 231 is positioned downstream of the pumping part 232 inorder to ensure a better mixing of the fluid to be activated and theactivation fluid.

The activated fluid is injected into the well-bore through the outlet208 downstream of the engine part 231 via for example a typical casingshoe CS2.

The injecting apparatus 201 for the second application operates asfollows.

In the rest configuration shown in FIG. 6.B, the injecting apparatus 201can be used to deliver a non activated fluid F1″ into the well-bore. Thesliding sleeve 221 of the valve arrangement 202 is positioned into themandrel 209 so that the fluid flowing into the mandrel is divertedthrough the first openings 224 into the shunt tube 210 towards theoutlet 208.

In order to activate the valve arrangement, a double dart assembly DD islaunched from the surface and transported by the fluid that is to beactivated.

In the activated configuration shown in FIG. 6.C, the injectingapparatus 201 is used to deliver an activated fluid F2 into the annulusAN of the well-bore WB.

The superior dart catcher 222C receives the double dart assembly DDtransported by the fluid. When the double dart assembly DD lands in thesuperior dart catcher, the double dart assembly acts as a plug andblocks the fluid flow. Consequently, the upstream pressure rises, thuscreating a downward load that liberates a small dart 227. The inferiordart catcher 222A receives the dart 227 transported by the fluid. Thedart catcher 222A is for example a particular profile of the slidingsleeve (narrow area) for stopping and sealing the dart 227. Once again,when the dart lands in the dart catcher 222A, the sliding sleeve acts asa plug and blocks the fluid flow. Consequently, the upstream pressurerises, thus creating a downward load that moves the sleeve in theactivated configuration. When the sliding sleeve is maintained in therest configuration by a pin mechanism, the downward load shears the pins221B and releases the sliding sleeve. The sliding sleeve 221 slidesdownward in the mandrel and the top part 221 A of the sliding sleevebump into the abutment 209A of the mandrel.

In this configuration, the sliding sleeve 221 simultaneously closes theshunt tube 210 and diverts the flow through the second opening 224′towards the engine part 231. The engine part 231 begins to rotate andmakes the pumping part 232 to rotate, thus sucking the activation fluidAF out of the reservoir 203.

The activation fluid flow FA and the fluid flow F1′ to be activatedmixes together downstream of the pumping part 232. An activated fluidflow F2 is delivered in the annulus AN of the well-bore WB.

As shown on the Figures, the double dart assembly may comprise anadditional valve avoiding the activated fluid (e.g. cement) in theannulus of greater density than fluid (generally mud) within the casingto flow back to the surface in the casing.

FIGS. 7.A, 7.B, 7.C relate to a third application corresponding to acasing cementation in a casing-drilling configuration. The casing CS3 isalready in place and the injecting apparatus 301 is pumped through thecasing and lands above the casing shoe CS4. The injecting apparatus 301is activated by a dart 327 sent from the surface through the casing. Theinjecting apparatus 301 may be drilled out at the end of the cementingoperation.

FIGS. 7.B and 7.C shows a detailed cross-section view of the injectingapparatus 301 in a rest configuration and in an activated configurationrespectively.

The injecting apparatus 301 comprises a valve arrangement 302, areservoir 303 and a dosing and mixing arrangement 304.

The valve arrangement 302 comprises a mandrel 309 and a sliding sleeve321.

The mandrel 309 is a tube having an inferior diameter than the casingCS3 diameter. It receives the fluid flowing through the casing via theinlet 307. Because of the significant difference between the casinginternal diameter and the mandrel inside diameter, a double dartassembly DD′ is used. The mandrel 309 is coupled by a top part to asuperior dart catcher 322C having a size substantially corresponding tothe internal size of the casing. The superior dart catcher 322C isadapted to receive the double dart assembly DD′ transported by thefluid. The mandrel 309 is coupled by a bottom part to a shunt tube 310.The shunt tube comprises an abutment 309A under the bottom part of themandrel. The sliding sleeve 321 is guided within the mandrel. Thesliding sleeve 321 comprises an inferior dart catcher 322A.

The valve arrangement can be in a rest configuration (FIG. 7.B) or in anactivated configuration (FIG. 7.C).

In the rest configuration, the fluid flowing into the mandrel flowsthrough the sliding sleeve and is diverted into the shunt tube 310. Thesliding sleeve 321 can be maintained in the rest configuration by, forexample, a pin mechanism or sealing mechanism.

In the activated configuration, enable the fluid flowing into themandrel is diverted through an opening 324 into the dosing and mixingarrangement 304. The sliding sleeve 321 is maintained in the activatedconfiguration when it is in contact with the abutment 309A.

The inferior dart catcher 322A enables to activate the valve arrangementfrom the rest configuration to the activated configuration.

The reservoir 303 is an annular bladder, for example made in rubbermaterial. The annular bladder is installed around the mandrel 309.

The top extremity of the bladder comprises a filling hose 303B closed bya top plug 303A. The bottom extremity of the bladder comprises anevacuation hose closed by a bottom plug 303D. The extremities of thesehoses are secured in the injecting apparatus near both extremities ofthe mandrel. The plugs can be removed to fill or flush the reservoir.The top plug 303A or the bottom plug 303D may be equipped with a reliefvalve for automatically venting the air trapped in the bladder.

The reservoir is connected to the dosing and mixing arrangement 304 by areservoir conduit 303E.

The pressure of the reservoir 303 is automatically adjusted to thepressure inside the casing and/or in the mandrel by means of at leastone equalization port 303C drilled in the mandrel 309. The equalizationport 303C operates as follows: the fluid in the mandrel penetrates inthe equalization port and exerts its pressure onto the reservoir, thuspressurizing the reservoir. When the reservoir is an annular bladder, itis deformed until the pressures outside and inside the reservoir areequilibrated.

The dosing and mixing arrangement 304 comprises an engine part 331mechanically coupled to a pumping part 332. Advantageously, the enginepart 331 is a progressive cavity or helical rotor type pump and thepumping part 332 is a peristaltic pump. The progressive cavity pump iscoupled to the peristaltic pump by a driving shaft 333. The end of thereservoir conduit 303E is a flexible tube coupled to the peristalticpump. The engine part 331 is driven by any fluid flowing through it.When a fluid flows through the engine part 331, it makes the pumpingpart 332 to rotate. The rotation of the peristaltic pump alternativelycompresses and releases the flexible tube of the reservoir conduit 303E,thus sucking the activation fluid AF out of the reservoir 303. Theengine part 331 is positioned downstream of the pumping part 332 inorder to ensure a better mixing of the fluid to be activated and theactivation fluid. Thus the engine part 331 also acts as a mixingarrangement 305.

The activated fluid is injected into the well-bore through the outlet308 downstream of the engine part 331 via for example a typical casingshoe CS4.

The injecting apparatus 301 for the third application operates asfollows.

In the rest configuration shown in FIG. 7.B, the injecting apparatus 301can be used to deliver a non activated fluid F1″ into the well-bore. Thesliding sleeve 321 of the valve arrangement 302 is positioned at thebottom of the mandrel 309 so that the fluid flowing into the mandrelflow through the sliding sleeve into the shunt tube 310 towards theoutlet 308.

In order to activate the valve arrangement, a double dart assembly DD′is launched from the surface and transported by the fluid that is to beactivated.

In the activated configuration shown in FIG. 7.C, the injectingapparatus 301 is used to deliver an activated fluid F2 into the annulusAN of the well-bore WB.

The superior dart catcher 322C receives the double dart assembly DD′transported by the fluid. When the double dart assembly DD′ lands in thesuperior dart catcher, F the double dart assembly acts as a plug andblocks the fluid flow. Consequently, the upstream pressure rises, thuscreating a downward load that liberates a small dart 327. The inferiordart catcher 322A receives the dart 327 transported by the fluid. Thedart catcher 322A is for example a particular profile of the slidingsleeve (narrow area) for stopping and sealing the dart 327. Once again,when the dart lands in the dart catcher 322A, the sliding sleeve acts asa plug and blocks the fluid flow. Consequently, the upstream pressurerises, thus creating a downward load that moves the sleeve in theactivated configuration. The sliding sleeve 221 slides downward andbumps into the abutment 309A.

In this configuration, the sliding sleeve 321 simultaneously closes theshunt tube 310 and diverts the flow through the opening 324 towards theengine part 331. The engine part 331 begins to rotate and makes thepumping part 332 to rotate, thus sucking the activation fluid AF out ofthe reservoir 303.

The activation fluid flow FA and the fluid flow F1′ to be activatedmixes together downstream of the pumping part 332. An activated fluidflow F2 is delivered in the annulus AN of the well-bore WB.

As shown on the Figures, the double dart assembly may comprise ahadditional valve avoiding the activated fluid (e.g. cement) in theannulus of greater density than fluid (generally mud) within the casingto flow back to the surface in the casing.

It is to be noted that the peristaltic pump described in relation withthe embodiments of FIGS. 5 to 7 may, alternatively, be equipped withseveral flexible tubes. In this case, the peristaltic pump may bedesigned to press simultaneously the several flexible tubes. Each tubemay be fitted with a valve in order to adjust, for a given application,the activation fluid flow-rate to be injected in the fluid.

It is to be mentioned that the invention is not limited to onshorehydrocarbon well and can also be used in relation with offshorehydrocarbon well.

Also, a particular application of the invention relating to the oilfieldindustry has been described. However, the invention is also applicableto other kind of industry, e.g. the construction industry or the like.

The drawings and their description hereinbefore illustrate rather thanlimit the invention.

Any reference sign in a claim should not be construed as limiting theclaim. The word “comprising” does not exclude the presence of otherelements than those listed in a claim. The word “a” or “an” preceding anelement does not exclude the presence of a plurality of such element.

1. An injection apparatus for injecting an activated fluid into awell-bore, the apparatus comprising a reservoir for containing anactivation fluid (AF), wherein the injection apparatus furthercomprises: a valve arrangement adapted to be coupled to a pipe forreceiving a first fluid (F1) flow, a dosing and mixing arrangementcoupled to the reservoir and to the valve arrangement, and wherein: thevalve arrangement has a rest configuration in which the injectionapparatus provides a non-activated fluid mixture (F1″) and an activatedconfiguration in which the injection apparatus provides an activatedfluid mixture (F2), the dosing and mixing arrangement comprising anengine part mechanically coupled to a pumping part, the engine partrunning the pumping part and the pumping part sucking the activationfluid (AF) of the reservoir when the valve arrangement is in theactivated configuration, and the dosing and mixing arrangement mixes theactivation fluid (AF) with the first fluid and provides an activatedfluid mixture flow (F2) at an outlet the valve arrangement is coupled tothe outlet by a second shunt tube and the valve arrangement further hasa by-pass configuration in which a second portion (F1″) of the firstfluid flows directly to the outlet, and wherein the activating steps areremotely controlled from a surface equipment.
 2. An injection apparatusaccording to claim 1, wherein the injection apparatus further comprisesa pressure adjusting arrangement for adjusting the pressure inside thereservoir to the pressure inside the pipe.
 3. An injection apparatusaccording to claim 2, wherein the pressure adjusting arrangementcomprises a piston fitted in the reservoir, said piston pressurizing theactivation fluid (AF) of the reservoir when the valve arrangementcoupled to the reservoir submits the piston to a third portion (F1′″) ofthe first fluid.
 4. An injection apparatus according to claim 2, whereinthe pressure adjusting arrangement comprises a reservoir consisting of abladder, said reservoir being coupled by at least one equalization portto a part of the injection apparatus submitted to the pressure insidethe pipe.
 5. An injection apparatus according to claim 4, wherein thepart of the injection apparatus submitted to the pressure inside thepipe is the valve arrangement.
 6. An injection apparatus according toclaim 1, wherein the valve arrangement comprises a sliding sleeve havinga first dart catcher for remotely activating the valve arrangement fromthe rest configuration to the activated configuration.
 7. An injectionapparatus according to claim 6, wherein the sliding sleeve has a seconddart catcher for remotely activating the by-pass configuration of thevalve arrangement.
 8. An injection apparatus according to claim 1,wherein the engine part is coupled to the pumping part through a gearingpart, the gearing part defining a volume ratio between the first portion(F1′) of the first fluid and the activation fluid (AF).
 9. An injectionapparatus according to claim 8, wherein the gearing part is a drivingshaft.
 10. An injection apparatus according to claim 1, wherein theengine part is a progressive cavity pump.
 11. An injection apparatusaccording to claim 1, wherein the pumping part is a progressive cavitypump.
 12. An injection apparatus according to claim 1, wherein thepumping part is a peristaltic pump.
 13. An injection apparatus accordingto claim 1, wherein the dosing and mixing arrangement further comprisesa complementary mixing arrangement comprising: a pre-mixing chambercoupled to the engine part and the pumping part, and a final mixingchamber coupled to the engine part and the pre-mixing chamber.
 14. Aninjection apparatus for injecting an activated fluid mixture into awell-bore according to claim 13, wherein the pre-mixing chamber iscoupled to the pumping part by a Venturi type injecting conduit.